During the last 6 years we have continued to coordinate distribution of ovine vessels and human umbilical cords, and isolate, purify, and characterize UAEC and HUVEC-CS cells for usage of all four projects. All of these cells are now very well characterized. Recently, we have also established primary HUVE and HUAEC, All primary human endothelial cells retain many normal in vivo physiologic functions such as in responses to growth factors and expression of key genes responsible for vasodilator production (NO), which are the cell responses we will determine in this Program Project Grant. Core C has frozen down many vials of UAEC, HUVEC, and HUAEC stocks for usage of the current application. We have also established standard immunocytochemistry protocols for colorimetric and fluorescent microscopy analysis, and transmission electron microscopy (TEM) analysis for Gap junction ultra-structural morphology. Thus, by acting as a Core, we will provide essential cell supplies, much needed technical expertise in NO detection and immunocytochemistry, TEM, and quality assurance, so contributing to the ability to directly compare data from different projects and between cell types.